<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
			<input id="num1" />+<input id="num2" />
			<input type="button" value="=" onclick="jisuan()" />
			<input id="num3" />
		<script>
			var jisuan=function(){
				num3.value=parseFloat(num1.value)+parseFloat(num2.value)
			}
		</script>
	</body>
</html>
